If I'm not wrong, when you use "fullbright" in that client, it actually just changes the "gamma" area in the options.txt folder to a high value, which carries over to all versions that use the folder the specific options.txt is in.
This is most likely a server plugin, as you are on a server (as told by the right side)
Wrong site for this.
If I'm not wrong, when you use "fullbright" in that client, it actually just changes the "gamma" area in the options.txt folder to a high value, which carries over to all versions that use the folder the specific options.txt is in.